こっそり (translations)→ creep discreetly furtively privately quietly sott-voce stealthily unperceived unseen
それとなく (translations)→ absently carelessly casual casually cautiously covertly cunningly delicately discreet friendly generally gently little obliquely somehow subtly unobtrusively vague veiled
ひそかに (translations)→ mentally private secretly silently softly unadvertised
